Rotary atomizer

Abstract

The invention relates to a rotary atomizer (1) for atomizing a coating agent (e.g. paint), comprising a rotor (2, 5) with a rotating magnet (5) and a stationary magnet sensor (6) for detecting the pole change of the magnetic field of the magnet (5), said pole changing as a result of the rotating rotor (2, 5). The magnet sensor (6) is arranged within the detection range about the magnet (5) such that the magnet sensor (6) can detect the pole change of the magnetic field. According to the invention, only materials which have a poor electric conductivity are located within the detection range about the rotating magnet (5), said materials having a high specific electric resistance of more than 1 Q.mm2Jm, 0.5 Ω.mm2 / m, or 0.1 Q.mm2Jm, in order to prevent induction currents which cause interference in the detection range, and / or only materials which have a good electric conductivity are located outside of the detection range about the rotating magnet (5), said materials having a low specific electric resistance of less than 1 Ω.mm 2 / m, 0.5 Ω.mm2 / m, or 0.1 Ω.mm2 / m.

Description

[0001] DESCRIPTION

[0002] Rotary atomizer

[0003] Technical field of the invention

[0004] The invention relates to a rotary atomizer for atomizing a coating agent, in particular for atomizing paint for painting motor vehicle body components.

[0005] Background of the invention

[0006] In modern paint shops for painting automotive body components, rotary atomizers are typically used as application equipment. When using such rotary atomizers, it is desirable to determine the speed and direction of rotation of the rotary atomizer to enable control or regulation of the speed.

[0007] DE 102 37 128 A1 discloses a rotary atomizer that allows the rotational speed and direction of rotation of the rotary atomizer to be monitored during operation. For this purpose, the known rotary atomizer features a rotating reflector disc that is scanned by an optical sensor. A disadvantage of this optical speed detection, however, is its susceptibility to interference caused by contamination of the reflector disc.

[0008] Furthermore, it is known from the prior art to acoustically determine the speed of a rotary atomizer by recording the operating noise of the rotary atomizer and deriving the speed from it. However, this acoustic speed detection is also susceptible to interference. For example, the ambient noise occurring during operation of a rotary atomizer in a paint shop can interfere with the acoustic speed measurement.

[0009] Finally, DE 10 2021 101 028 A1 discloses measuring the rotational speed of a rotary atomizer using a Wiegand sensor (pulse wire sensor), which detects the rotating pole changes of a rotating magnetic disk. However, this type of rotational speed detection using a Wiegand sensor is also susceptible to interference, and the technical and physical reasons for the interference sensitivity of rotational speed measurement using a Wiegand sensor have not yet been fully understood. Finally, for the general technical background of the invention, reference should be made to WO 2022 / 157 098 A1, JP 2018-58 015 A, and EP 2 383 546 A1.

[0010] Description of the invention

[0011] The invention is therefore based on the object of improving the speed detection in a rotary atomizer.

[0012] This object is achieved by a rotary atomizer according to the invention according to the main claim.

[0013] The rotary atomizer according to the invention, in accordance with known rotary atomizers, comprises a rotatably mounted rotor that rotates around a rotational axis at a specific speed during operation. In a preferred embodiment of the invention, the rotor comprises an atomizer shaft, which has a mounting option for a bell cup at its distal end, for example, in the form of a screw connection for screwing the bell cup onto the atomizer shaft.

[0014] Furthermore, the rotary atomizer according to the invention, in accordance with the rotary atomizers with a Wiegand sensor described above in the prior art, also has a magnet (e.g. magnetic disk) which rotates with the rotor and has several magnetic poles distributed over the circumference and thus a pole change in the circumferential direction.

[0015] In addition, the rotary atomizer according to the invention also contains a magnetic sensor (e.g. Wiegand sensor) for detecting the pole changes of the magnetic field of the magnet rotating with the rotating rotor, wherein the magnetic sensor is arranged within a detection range around the magnet so that the magnetic sensor can detect the rotating pole changes of the magnetic field.

[0016] The invention is based on the newly acquired technical-physical insight that the rotating pole changes of the magnetic field in the materials of the rotary atomizer lead to eddy currents and induce opposing magnetic fields that interfere with the speed measurement by the magnetic sensor (e.g., Wiegand sensor). Thus, at the location of the magnetic sensor (e.g., Wiegand sensor), a useful signal resulting from the rotating pole changes of the rotating magnet is superimposed on an interference signal generated by the induced opposing magnetic fields. The invention therefore provides for the reduction of these disruptive eddy currents and opposing magnetic fields in order to reduce the susceptibility of the speed measurement to interference.

[0017] In the rotary atomizer according to the invention, therefore, only electrically poorly conductive materials with a high specific electrical resistance of more than 1 Ω.mm are preferably located within the detection range around the rotating magnet. 2 / m, 0.5 µm 2 / m or 0.1 Ωmm 2 / m to avoid disturbing induction currents in the detection area.

[0018] Outside the detection range, however, even with the rotary atomizer according to the invention, there may be electrically conductive materials that have a low specific electrical resistance of less than 1 Q.mm 2 / m, 0.5 µm 2 / m or 0.1 Ωmm 2 / m have.

[0019] The rotary atomizer according to the invention is therefore preferably characterized by a material mix, wherein the material mix within the detection range around the rotating magnet contains electrically poorly conductive materials (e.g. p > 0.1 Q.mm 2 / m), while outside the detection range around the rotating magnet, electrically conductive materials (e.g. p < 0.1 Q.mm 2 / m), as is the case with conventional rotary atomizers.

[0020] The above-mentioned materials with poor electrical conductivity may be, for example, plastic, stainless steel or titanium, but the invention is not limited to these examples with regard to the materials with poor electrical conductivity.

[0021] In the preferred embodiment of the invention, the stationary magnetic sensor is spatially separated from the rotating magnet by an air gap, which can have a gap width of at least 0.1 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, or 10 mm. The air gap completely prevents the induction of currents and opposing fields in the area of ​​the air gap, since air is electrically insulating.

[0022] With regard to the design of the rotating magnet, there are various possibilities within the scope of the invention, two variants of which are described below. In one variant of the invention, the magnet is shaped as a magnetic disk, wherein the magnetic disk is arranged coaxially to the axis of rotation and rotates with the rotor of the rotary atomizer. For example, the magnetic disk can be pressed onto the atomizer shaft, to name just one example. The magnetic sensor is preferably located proximally behind the magnetic disk in the axial direction and is separated from the magnetic disk in the axial direction by the aforementioned air gap. In this variant, the magnetic field therefore runs essentially axially in the air gap. The length of the magnetic disk in the axial direction is significantly smaller than the radius of the magnetic disk.Furthermore, it should be noted that the at least one magnet is preferably embedded in an end face of the magnetic disk. If the magnetic sensor is arranged proximally in front of the magnetic disk (i.e., on the side of the painting robot and on the side facing away from the bell cup), the at least one magnet is then also embedded in the proximal end face of the magnetic disk.

[0023] In another variant of the invention, however, the rotating magnet is shaped as a magnetic sleeve, which can, for example, be pressed onto the atomizer shaft. The magnetic sensor (e.g. Wiegand sensor) is radially separated from the rotating magnetic sleeve by the aforementioned air gap. In the air gap between the rotating magnetic sleeve on the one hand and the stationary magnetic sensor on the other, the magnetic field in this variant therefore runs essentially radially. The magnetic sensor in this variant is therefore preferably arranged radially outside the magnetic sleeve. With regard to the design of such a magnetic sleeve, it should be mentioned that the magnetic sleeve is hollow and has a radial thickness that is significantly smaller than the axial length and / or the radius of the magnetic sleeve.

[0024] In the preferred embodiment of the invention, the magnetic sensor is arranged in an annular space which extends in the circumferential direction. For example, the annular space can extend over the entire circumference around the axis of rotation. In the preferred embodiment of the invention, however, the annular space consists of at least one elongated hole which is curved in the circumferential direction and extends only over part of the circumference. The magnetic sensor is arranged in the elongated hole, preferably centrally with respect to the circumferential direction, so that the magnetic sensor is surrounded by the elongated hole on both sides in the circumferential direction. Furthermore, it should be mentioned that the magnetic sensor preferably does not completely fill the annular space (e.g. elongated hole) in the radial direction, but leaves a free space radially on the inside.

[0025] The annular space (e.g., elongated hole) is preferably filled with an electrically insulating material, which largely prevents the induction of eddy currents and opposing magnetic fields in the vicinity of the magnetic sensor, since eddy currents cannot form in the electrically insulating material. Filling the annular space (e.g., elongated hole) with an electrically insulating material is also advantageous for preventing air turbulence in the annular space, which can otherwise occur in a hollow annular space and lead to mechanical power losses. For example, the electrically insulating material in the annular space can be plastic.

[0026] Furthermore, the invention encompasses a further inventive concept of its own worthy of protection. For example, disruptive eddy currents and opposing magnetic fields can also be reduced by using a laminated core consisting of numerous laminations that are electrically insulated from one another, so that no eddy current can flow across the laminations. Such laminated cores are already known from transformers and therefore need not be described in more detail. For example, the laminated core can contain more than 10, 20, 50, or 70 laminations that are electrically insulated from one another.

[0027] It is possible that the magnetic sensor (e.g. Wiegand sensor) is arranged at least partially in the laminated core, for example in an axial bore in the laminated core.

[0028] It should also be mentioned that the individual laminations of the laminated core preferably each lie in a plane that contains the rotational axis of the rotary atomizer. The individual laminations are therefore preferably distributed around the circumference with respect to the rotational axis. The entire laminated core is therefore preferably arranged in a ring shape and coaxial with the rotational axis of the rotor. Furthermore, there is the possibility that at least some of the laminations of the laminated core are slotted in order to optimally suppress the disruptive eddy currents. The laminations can, for example, consist of a so-called mu-metal, whereby such mu-metals are known per se from the prior art. In general, it should be mentioned that the adjacent laminations of the laminated core can each be separated by an air gap, whereby the air gaps can also be filled with an electrically insulating material.Furthermore, it should be mentioned that the laminated core is preferably arranged within the detection range around the magnet.

[0029] As already mentioned above, the invention aims to minimize interference with speed measurement caused by induced opposing fields. Thus, the magnetic field generated by the rotating magnet generates a useful signal with a maximum first magnetic field strength. The interfering opposing magnetic field generated by the induced currents, in contrast, generates an interference signal with a second maximum magnetic field strength at the location of the magnetic sensor. The interference suppression measures according to the invention preferably enable a reduction of the second maximum magnetic field strength (interference signal) of the interfering opposing magnetic field to 30%, 20%, 10%, 5%, or even just 2% of the first maximum magnetic field strength of the useful signal generated by the rotating magnet. As a result, the design measures according to the invention improve the useful signal / interference signal ratio in magnetic speed measurement.

[0030] Furthermore, it should be noted that various orientations and arrangements of the magnetic sensor within the rotary atomizer are possible within the scope of the invention. For example, the magnetic sensor can be elongated and aligned with its longitudinal axis parallel to the rotational axis of the rotary atomizer. Alternatively, the magnetic sensor can be elongated and aligned with its longitudinal axis radially relative to the rotational axis of the rotary atomizer.

[0031] With the aforementioned axial alignment of the magnetic sensor parallel to the rotational axis of the rotary atomizer, various arrangements of the magnetic sensor are possible. For example, the magnetic sensor can be arranged proximally in front of the magnetic disk in the axial direction, so that the annular air gap separates the magnetic sensor from the magnetic disk in the axial direction. However, it is also possible for the magnetic sensor to partially overlap the magnetic disk in the axial direction and to be arranged on the circumference of the magnetic disk radially outside the magnetic disk. The annular air gap then separates the magnetic sensor from the magnetic disk in the radial direction.

[0032] With the aforementioned radial orientation of the magnetic sensor, there are also various possibilities for arranging the magnetic sensor within the scope of the invention. For example, the magnetic sensor can be arranged proximally in front of the magnetic disk in the axial direction, so that the air gap separates the magnetic sensor from the magnetic disk in the axial direction. In this case, the magnetic sensor then overlaps with the magnetic disk in the radial direction. Alternatively, however, it is also possible for the radially aligned magnetic sensor to be arranged on the circumference of the magnetic disk radially outside the magnetic disk, so that the air gap separates the magnetic sensor from the magnetic disk in the radial direction. It has already been mentioned above that the magnetic sensor is preferably a Wiegand sensor, as is known per se from the prior art (e.g. DE 10 2021 101 028 A1).Such Wiegand sensors are also referred to as pulse wire sensors and do not need to be described in more detail since they are known per se from the prior art. However, the invention is not limited to a Wiegand sensor with regard to the type of magnetic sensor.

[0033] Furthermore, it should be noted in general that the rotor preferably has the magnetic sensor as a separate component that is non-rotatably connected to the rotor. For example, the magnetic sensor (e.g., magnetic disk, magnetic sleeve) can be pressed onto the atomizer shaft, to name just one example.

[0034] It should also be mentioned that the rotary atomizer can have a compressed air turbine to drive the rotor, as is the case with conventional rotary atomizers.

[0035] In the preferred embodiment of the rotary atomizer according to the invention, the rotating magnet has several pairs of magnetic north poles and magnetic south poles alternating over its circumference, for example two, three or four pairs of magnetic poles.

[0036] Regarding the aforementioned detection range around the magnet, it should be noted that the detection range along the rotation axis preferably extends over an axial dimension that can be in the range of 5 mm - 5 cm. In the radial direction, however, the detection range preferably has a radial dimension that can be in the range of 5 mm - 3 cm.

[0037] It was already mentioned at the beginning that with a rotary atomizer it is desirable to detect not only the speed but also the direction of rotation. In the rotary atomizer according to the invention, the distribution of the magnetic poles over the circumference of the rotor is therefore preferably not rotationally symmetrical in order to be able to detect both the speed and the direction of rotation of the rotor. With a rotationally symmetrical arrangement of the magnetic poles, the pulse sequence supplied by the magnetic sensor contains no information about the direction of rotation of the rotary atomizer. This is different with a non-rotationally symmetrical arrangement of the magnetic poles in the rotor, since the pulse sequence supplied by the magnetic sensor then also contains information about the direction of rotation of the rotary atomizer. Furthermore, it should be mentioned in general that the rotary atomizer according to the invention is preferably designed for atomizing paint when painting motor vehicle body components.However, the invention is not limited to paints with regard to the coating agent to be atomized, but can also be implemented with other types of coating agents. Furthermore, the rotary atomizer according to the invention is suitable not only for coating motor vehicle body components, but also for coating other types of components.

[0038] Finally, the invention also encompasses the novel use of a rotary atomizer according to the invention for atomizing paint, particularly in the painting of motor vehicle body components. The paint can be, for example, wet paint (liquid paint) or powder paint. Furthermore, it should be noted that the invention is not limited to motor vehicle body components with regard to the components to be painted, but is also suitable for painting other types of components.

[0039] Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred embodiments of the invention with reference to the figures.

[0040] Brief description of the drawings

[0041] Figure 1A shows a sectional view through a rotary atomizer according to the invention.

[0042] Figure 1B shows an enlarged detail view of Figure 1A.

[0043] Figure 2 shows a perspective view of a magnetic disk used in the rotary atomizer according to the invention for speed detection.

[0044] Figure 3 shows an axial rear view of the rotary atomizer according to the invention.

[0045] Figure 4 shows a magnetic sleeve as an alternative to the magnetic disc according to Figure 2.

[0046] Figure 5 shows a sectional view through a modified rotary atomizer with a laminated core to minimize disruptive eddy currents.

[0047] Figure 6 shows an axial rear view of the rotary atomizer according to Figure 5. Figure 7 shows a schematic representation of a modified magnetic disk with a non-rotationally symmetrical arrangement of the magnetic poles in order to also enable detection of the direction of rotation.

[0048] Figures 8-10 show various modifications according to the invention with different arrangements of the magnetic sensor.

[0049] Detailed description of the drawings

[0050] The embodiment of a rotary atomizer 1 according to the invention shown in the drawings will now be described, wherein Figure 1A shows a sectional view of a part of the rotary atomizer 1.

[0051] Thus, the rotary atomizer 1 initially comprises, in a conventional manner, an atomizer shaft 2, which is part of a rotor and rotates about a rotational axis 3 during operation (see Figures 3, 5, and 6). The atomizer shaft 2 is driven in a conventional manner by a compressed air turbine, which is not shown for simplicity.

[0052] The atomizer shaft 2 is rotatably mounted within an atomizer housing 4 in a conventional manner, whereby the bearings for the atomizer shaft 2 are also not shown.

[0053] A magnetic disc 5 is pressed onto the atomizer shaft 2, which has several magnetic north poles N and magnetic south poles S distributed over the circumference, as can be seen in particular from Figure 2.

[0054] The speed is detected by a Wiegand sensor 6, which is arranged in the atomizer housing 4, wherein the Wiegand sensor 6 is separated from the magnetic disk 5 by an air gap 7. In the air gap 7, the magnetic field B generated by the magnetic disk 5 runs essentially axially, i.e. parallel to the axis of rotation 3 of the atomizer shaft 2. As the atomizer shaft 2 rotates with the magnetic disk 5, the direction of the magnetic field B in the air gap 7 changes continuously, i.e. pole changes occur in the air gap 7, which are detected by the Wiegand sensor 6 in the conventional way. It should also be mentioned that the Wiegand sensor 6 is arranged within a detection range 8 around the magnetic disk 5 so that the Wiegand sensor 6 can detect the pole changes generated by the rotating magnetic disk 5 in the air gap 7.The detection range 8 is shown only schematically to facilitate understanding of the invention. In fact, the detection range 8 does not have a circular or spherical shape.

[0055] The air gap 7 has a gap width of b=10 mm in the axial direction. This is advantageous because, due to the electrically insulating effect of the air, no eddy currents or opposing magnetic fields can be induced within the air gap 7, thus largely preventing interference with the speed measurement.

[0056] It should also be mentioned that the Wiegand sensor 6 is arranged in the atomizer housing 4 in an elongated hole 9 which extends in the circumferential direction, as can be seen from Figure 3. The Wiegand sensor 6 is arranged centrally in the elongated hole 9 with respect to the circumferential direction, so that the Wiegand sensor 6 is surrounded by the elongated hole 9 on both sides in the circumferential direction. It should also be mentioned that the Wiegand sensor 6 does not completely fill the elongated hole 9 in the radial direction, but leaves a radial free space 10 free radially on the inside. The arrangement of the Wiegand sensor 6 in the elongated hole 9 is advantageous because no disruptive induction currents or opposing fields can be induced within the elongated hole 9, which likewise reduces the sensitivity of the speed measurement to interference. It should be mentioned here that the elongated hole 9 can also be filled with an electrically insulating material, such as plastic.This is advantageous in order to avoid air turbulence in the slot 9, which would lead to mechanical power losses.

[0057] Figure 4 shows, as an alternative to the magnetic disk 5 according to Figure 2, a magnetic sleeve 11 which can, for example, be pressed onto an atomizer shaft. The magnetic sleeve 11 also has several magnetic north poles N and magnetic south poles S distributed over the circumference in order to generate pole changes upon rotation, as is also the case with the magnetic disk 5 according to Figure 2. However, the associated Wiegand sensor is preferably arranged radially on the outside and separated from the magnetic sleeve 11 by an air gap. In this variant with the magnetic sleeve 11, the magnetic field in the air gap between the magnetic sensor and the magnetic sleeve 11 runs essentially in the radial direction.

[0058] Figure 5 shows a modification of a rotary atomizer 1 according to the invention, which largely corresponds to the embodiment described above, so that in order to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

[0059] A special feature of this modified embodiment is that a laminated core 12 is arranged in the atomizer housing 4. The laminated core 12 has numerous laminated sheets 13 distributed over the circumference, as can be seen in particular from Figure 6, wherein the adjacent laminated sheets 13 are each separated from one another by an air gap 14. The laminated core 12 therefore prevents eddy currents from flowing in the circumferential direction, since the adjacent laminated sheets 13 are insulated from one another. The laminated core 12 therefore also contributes to avoiding the disruptive eddy currents that are generated when the magnetic disk 5 rotates. The Wiegand sensor 6 is arranged in an axial bore 15 that passes through the laminated core 12. Furthermore, it can be seen from Figure 6 that the individual laminated sheets 13 of the laminated core 12 each lie in a plane that contains the axis of rotation 3 of the rotary atomizer 1.In the sectional view according to Figure 6, the individual sheets 13 run in the radial direction.

[0060] Furthermore, Figure 7 shows a modification of the magnetic disk 5 according to Figure 2, wherein the same reference numerals are used for corresponding details, so that in order to avoid repetition, reference is first made to the above description of Figure 2.

[0061] A special feature of this embodiment is that the magnetic north poles N and the magnetic south poles S are not arranged rotationally symmetrically over the circumference of the magnetic disk 5. This offers the advantage of not only allowing a rotational speed measurement but also a determination of the direction of rotation. Due to the non-rotationally symmetrical arrangement of the magnetic north poles N and the magnetic south poles S, the pulse sequence supplied by the magnetic sensor contains not only information about the speed but also information about the direction of rotation of the rotary atomizer.

[0062] The invention is not limited to the preferred embodiments described above. Rather, the invention also encompasses variants and modifications which likewise make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and features of the subclaims independently of the respective claims referred to and in particular also without the features of the main claim. The invention therefore encompasses various aspects of the invention which are protected independently of one another. This applies in particular to the idea of ​​using a laminated core in a rotary atomizer to minimize eddy currents. The idea of ​​using a laminated core in a rotary atomizer to avoid eddy currents can therefore also be implemented within the scope of the invention without the special arrangement of materials with good or poor electrical conductivity within or around the main claim.outside the detection range.

[0063] Finally, Figures 8-10 show various modifications according to the invention with different arrangements of the magnetic sensor 6. These modifications largely correspond to the embodiments described above, so that in order to avoid repetition, reference is made to the above description, the same reference numerals being used for corresponding details.

[0064] In the embodiment according to Figure 8, the magnetic sensor 6 is elongated and aligned with its longitudinal axis parallel to the rotational axis 3 of the rotor, as is also the case in the embodiment according to Figure 1A. In the embodiment according to Figure 1A, however, the magnetic sensor 6 is arranged proximally in front of the magnetic disk 5 in the axial direction, whereas in this embodiment the magnetic sensor 6 partially overlaps the magnetic disk 5 in the axial direction and is arranged on the circumference of the magnetic disk 5 radially outside the magnetic disk 5. The air gap 7 is therefore annular and separates the magnetic sensor 6 from the magnetic disk 5 in the radial direction.

[0065] In Figure 9, the magnetic sensor 6 is also elongated. However, the magnetic sensor 6 is aligned with its longitudinal axis radially relative to the rotation axis 3. The magnetic sensor 6 is arranged on the circumference of the magnetic disk 5, radially outside the magnetic disk 5, and is separated from the magnetic disk 5 in the radial direction by the annular air gap 7.

[0066] Finally, Figure 10 also shows the magnetic sensor 6 in a radial orientation relative to the rotational axis 3 of the rotor. However, the magnetic sensor 6 is arranged proximally in front of the magnetic disk 5 in the axial direction and partially overlaps with the magnetic disk 5 in the radial direction. The annular air gap 7 thus separates the magnetic sensor 6 from the magnetic disk 5 in the axial direction.

[0067] Advantages of the invention Some advantages of the invention are briefly summarized below.

[0068] • The invention enables interference-insensitive detection of speed and direction of rotation in a rotary atomizer, which in turn enables reliable control and leads to shorter downtimes.

[0069] • In addition, the invention enables higher signal reserves for more stable control.

[0070] • Furthermore, the speed detection is less sensitive to external interference.

[0071] • In addition, the rotary atomizer according to the invention has a higher efficiency and thus has a lower air consumption across all operating points due to lower eddy current losses or lower air vortex losses.

[0072] • Finally, due to the clearances (e.g. air gap, elongated hole) a lighter construction of the rotary atomizer is possible.

[0073] List of reference symbols

[0074] 1 rotary atomizer

[0075] 2 atomizer shaft

[0076] 3 Rotation axis of the rotor

[0077] 4 atomizer housings

[0078] 5 magnetic disc

[0079] 6 Wiegand sensor

[0080] 7 Air gap between the magnetic disk and the Wiegand sensor

[0081] 8 Detection range

[0082] 9 Slot for the Wiegand sensor

[0083] 10 Radial clearance on the inside of the Wiegand sensor

[0084] 11 Magnetic sleeve

[0085] 12 sheet package

[0086] 13 sheets

[0087] 14 Air gaps between the adjacent sheets of the laminated core

[0088] 15 Axial bore in the laminated core for accommodating the Wiegand sensor b Gap width of the air gap between the magnetic disc and the Wiegand sensor

[0089] N Magnetic North Poles

[0090] S Magnetic South Poles

[0091] B Magnetic field in the air gap

Claims

Claims 1. Rotary atomizer (1) for atomizing a coating agent, in particular for atomizing paint for painting motor vehicle body components, with a) a rotatably mounted rotor (2, 5, 11) which rotates at a specific speed about a rotational axis (3) during operation, b) a magnet (5, 11) which rotates with the rotor (2, 5, 11) and has a plurality of magnetic poles (N, S) distributed over the circumference and thus has a pole change in the circumferential direction, and c) a magnetic sensor (6) arranged in a fixed position in the rotary atomizer (1) for detecting the pole changes of the magnetic field (B) of the magnet (5, 11) rotating with the rotating rotor (2, 5, 11), wherein the magnetic sensor (6) is arranged within a detection range (8) around the magnet (5, 11), so that the magnetic sensor (6) detects the rotating pole changes of the magnetic field (B), characterized in that d) that within the detection range (8) around the rotating magnet (5,11) only electrically poorly conductive materials with a high specific electrical resistance of more than 1 Q.mm, 2 / m, 0.5 µm 2 / m or 0.1 Ωmm 2 / m, in order to avoid disturbing induction currents in the detection area, and / or e) that only outside the detection range (8) around the rotating magnet (5, 11) there are electrically highly conductive materials with a small specific electrical resistance of less than 1 Q.mm 2 / m, 0.5 µm 2 / m or 0.1 Ωmm 2 / m.

2. Rotary atomizer (1) according to claim 1, characterized by a material combination a) of the electrically poorly conductive materials within the detection range (8) around the rotating magnet (5, 11) and b) of the electrically highly conductive materials outside the detection range (8) around the rotating magnet (5, 11).

3. Rotary atomizer (1) according to one of the preceding claims, characterized in that the electrically poorly conductive material within the detection range (8) around the rotating magnet (5, 11) is plastic, stainless steel or titanium.

4. Rotary atomizer (1) according to one of the preceding claims, characterized in that a) the stationary magnetic sensor (6) is spatially separated from the rotating magnet by an air gap, and b) the air gap preferably has a gap width (b) of at least 0.1 mm, 0.5 mm, 1 mm, 2 mm, 5 mm or 10 mm.

5. Rotary atomizer (1) according to claim 4, characterized in that a) the magnet (5) is shaped as a magnetic disk (5), b) the magnetic sensor (6) is axially separated from the magnetic disk (5) by the air gap (7), c) the magnetic field (£?) in the air gap (7) runs essentially axially, d) the magnetic sensor (6) is preferably arranged proximally with respect to the magnetic disk (5) in the axial direction, e) the magnetic disk (5) is preferably arranged coaxially to the axis of rotation (3).

6. Rotary atomizer (1) according to claim 4, characterized in that a) the magnet (11) is shaped as a hollow magnet sleeve (11), b) the magnetic sensor is radially separated from the magnet sleeve (11) by the air gap, c) the magnetic field in the air gap runs substantially radially, d) the magnetic sensor is preferably arranged radially outside the magnet sleeve (11).

7. Rotary atomizer (1) according to one of the preceding claims, characterized in that a) the magnetic sensor (6) is arranged at least partially in an annular space (9) which extends in the circumferential direction, b) the annular space (9) optionally extends over the entire circumference around the rotation axis (3), c) the annular space (9) optionally has at least one elongated hole (9) which extends only over a part of the circumference around the rotation axis (3), d) the magnetic sensor (6) is optionally arranged centrally in the elongated hole (9) with respect to the circumferential direction, so that the magnetic sensor (6) is circumferentially arranged on both sides of the Elongated hole (9) is surrounded, e) that the magnetic sensor (6) optionally does not completely fill the annular space (9) in the radial direction, but leaves a free space (10) radially inside.

8. Rotary atomizer (1) according to one of the preceding claims, characterized in that a) the annular space (9) is at least partially filled with an electrically insulating material, b) the electrically insulating material in the annular space (9) is preferably plastic, c) the electrically insulating material in the annular space (9) preferably has a specific electrical resistance which is greater than 10 3 Q-mm 2 / m, 10 4 -mm 2 / m, 10 5 Q-mm 2 / m, 10 6 -mm 2 / m, 10 7 -mm 2 / m, 10 8 -mm 2 / m. 10 9 -mm 2 / m or IO 10 -mm 2 / m.

9. Rotary atomizer (1) according to one of the preceding claims, characterized by a laminated core (12) with numerous laminated cores (13) for reducing eddy current losses caused by the circulating pole changes of the magnetic field (£?) of the rotating magnet (5, 11).

10. Rotary atomizer (1) according to claim 9, characterized in that a) the magnetic sensor (6) is arranged at least partially in the laminated core (12), and / or b) the magnetic sensor (6) is arranged in an axial bore (15) in the laminated core (12).

11. Rotary atomizer (1) according to claim 9 or 10, characterized in that a) the individual sheets (13) of the laminated core (12) are each flat and each lie in a plane containing the rotational axis (3), and / or b) the individual sheets (13) are arranged distributed over the circumference with respect to the rotational axis (3), and / or c) the laminated core (12) is arranged annularly and coaxially to the rotational axis (3) of the rotor (2, 5, 11), and / or d) at least some of the sheets (13) of the laminated core (12) are slotted, and / or e) the sheets (13) consist of a mu-metal, and / or f) the adjacent sheets (13) of the laminated core (12) are each separated by an air gap (14), and / or g) that the laminated core (12) is preferably arranged within the detection range (8) around the magnet (5, 11).

12. Rotary atomizer (1) according to one of the preceding claims, characterized in that a) the magnetic field (B) generated by the rotating magnet (5, 11) as a useful signal has a first maximum magnetic field strength at the location of the magnetic sensor (6), b) the counter magnetic field generated by the induction currents as an interference signal has a second maximum magnetic field strength at the location of the magnetic sensor (6), and c) the second maximum magnetic field strength of the interference signal at the location of the magnetic sensor (6) is at most 30%, 20%, 10%, 5% or 2% of the first maximum magnetic field strength of the useful signal.

13. Rotary atomizer (1) according to one of the preceding claims, characterized in that the magnetic sensor (6) is elongated and is aligned with its longitudinal axis parallel to the rotation axis (3) of the rotor.

14. Rotary atomizer (1) according to claim 13, characterized in that a) the magnetic sensor (6) is arranged proximally in front of the magnetic disk (5) in the axial direction and is separated from the magnetic disk (5) in the axial direction by the air gap (7), and / or b) the magnetic field (B) in the air gap (7) runs essentially axially, and / or c) the magnetic sensor (6) is arranged at least partially within the maximum diameter of the magnetic disk (5).

15. Rotary atomizer (1) according to claim 13, characterized in that a) the magnetic sensor (6) at least partially overlaps with the magnetic disk (5) in the axial direction, and / or b) the magnetic sensor (6) is arranged radially outside the magnetic disk (5) and is separated from the magnetic disk (5) in the radial direction by the annular circumferential air gap (7), and / or c) the magnetic field (B) in the air gap (7) runs substantially radially, and / or d) the magnetic disk (6) is magnetized on its circumference.

16. Rotary atomizer (1) according to one of claims 1 to 12, characterized in that the magnetic sensor (6) is elongated and is aligned with its longitudinal axis radially with respect to the rotation axis (3) of the rotor.

17. Rotary atomizer (1) according to claim 16, characterized in that a) the magnetic sensor (6) is arranged on the circumference of the magnetic disk (5) radially outside the magnetic disk (5) and in axial overlap with the magnetic disk (5) and is separated from the magnetic disk (5) in the radial direction by the annular circumferential air gap (7), and / or b) the magnetic field (B) in the air gap (7) runs substantially radially, and / or c) the magnetic disk (6) is magnetized on its circumference.

18. Rotary atomizer (1) according to claim 16, characterized in that a) that the magnetic sensor (6) is arranged proximally in front of the magnetic disk (5) in the axial direction and is separated from the magnetic disk (5) in the axial direction by the air gap (7), and / or b) that the magnetic field (B) in the air gap (7) runs substantially axially.

19. Rotary atomizer (1) according to one of the preceding claims, characterized in that a) the magnetic sensor (6) is a Wiegand sensor (6), and / or b) the rotor (2, 5, 11) has the magnetic sensor (6) as a separate component, which is connected in a rotationally fixed manner to the rotor (2, 5, 11), and / or c) the rotor (2, 5, 11) has an atomizer shaft (2) which has a mounting option for a bell cup at its distal end, in particular in the form of a screw thread for screwing the bell cup onto the atomizer shaft, and / or d) the rotary atomizer (1) has a compressed air turbine to drive the rotor (2, 5, 11), and / or e) the rotating magnet (5, 11) has several pairs of magnetic north poles (N) and magnetic south poles (S) alternating over its circumference, in particular more than two, three or four pairs, and / or f) that the detection range (8) around the magnet (5,11) has an axial extension along the axis of rotation (3) of at most 5 cm, 3 cm, 2 cm, 1 cm and / or at least, 1 mm, 2 mm, 3 mm, 4 mm or 5 mm, and / or g) that the detection range (8) around the magnet (5, 11) in the radial direction with respect to the axis of rotation (3) has a radial extent which is at most 3 cm, 2 cm, 1 cm, 5 mm and / or at least 1 mm, 2 mm, 3 mm, 4 mm or 5 mm, and / or h) that the distribution of the magnetic poles (N, S) over the circumference of the rotor (2, 5, 11) is not rotationally symmetrical in order to be able to detect both the speed and the direction of rotation of the rotor (2, 5, 11), and / or i) that the magnetic sensor (6) can only detect the speed within the detection range (8), but not outside the detection range (8).

20. Use of a rotary atomizer (1) according to one of the preceding claims for atomizing liquid or powdered paint, in particular when painting motor vehicle body components.

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